Transceiver with a test mode of operation

ABSTRACT

A system comprising a host and a transceiver coupled to the host is provided where the transceiver is configured to receive a request from a host and cause a test mode of operation to be entered in response to receiving the request.

THE FIELD OF THE INVENTION

[0001] The present invention generally relates to transceivers and, moreparticularly, to a transceiver with a test mode of operation.

BACKGROUND OF THE INVENTION

[0002] Transceivers and other electronic devices may need calibration ortuning functions to be performed on one or more components of the devicebefore the device can be operated properly. Because the failure toperform these calibration or tuning functions correctly can cause atransceiver to malfunction, the calibration and tuning functions aregenerally performed by a manufacturer or an authorized servicetechnician. A customer or other end user of the transceiver is generallynot permitted to access any of the calibration or tuning functions.

[0003] In some transceivers, the calibration and tuning functions may beperformed on some components prior to the components being installed inthe transceiver. These transceivers may have the various parameters andconstants used in the calibration and tuning functions stored in thetransceiver such that this information is either not accessible by ahost connected to the transceiver or not alterable by such a host.

[0004] In other transceivers, however, the various parameters andconstants used in the calibration and tuning functions may be accessibleand/or alterable by a host. Although the information may be accessibleby a host, a manufacturer may wish to prevent a customer or end userfrom accessing or altering the information in the transceiver to ensureproper and safe operation of the device.

[0005] It would be desirable to be able to allow a manufacturer toaccess and alter certain information in a transceiver while preventingcustomer or end user from accessing or altering the information.

SUMMARY OF THE INVENTION

[0006] The present disclosure provides a system comprising a host and atransceiver coupled to the host where the transceiver is configured toreceive a request from a host and cause a test mode of operation to beentered in response to receiving the request.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a block diagram illustrating an embodiment of a systemthat includes a transceiver with a test mode of operation.

[0008]FIG. 2 is a flow chart illustrating an embodiment of a method forchanging modes of operation in a transceiver.

[0009]FIG. 3 is a flow chart illustrating an embodiment of a method forinteracting with a transceiver in a test mode of operation.

[0010]FIG. 4 is a flow chart illustrating an embodiment of a method fordetecting errors from a test mode of operation of a transceiver.

[0011]FIG. 5 is a block diagram illustrating an alternative embodimentof a system that includes a transceiver with a test mode of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following detailed description of the preferredembodiments, reference is made to the accompanying drawings which form apart hereof, and in which is shown by way of illustration specificembodiments in which the invention may be practiced. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope of thepresent invention. The following detailed description, therefore, is notto be taken in a limiting sense, and the scope of the present inventionis defined by the appended claims.

[0013] A transceiver with a test mode of operation is shown anddescribed herein. In response to being powered up or reset, atransceiver determines whether all calibration steps associated with thetransceiver have been completed. If all of the steps have not beencompleted, then the transceiver enters a test mode of operation andperforms calibration steps in conjunction with a host. After all of thesteps have completed successfully, the transceiver enters a customermode of operation and indicates its readiness to ship to an end user. Ifone or more steps do not complete successfully, the steps may be retriedand/or failure analysis techniques may be applied to the transceiver. Ahost may cause the transceiver to re-enter the test mode of operation byproviding an appropriate request to the transceiver.

[0014]FIG. 1 is a block diagram illustrating an embodiment of a system100 that includes a transceiver 120 with a test mode of operation. Asshown in FIG. 1, a host 110 is coupled to transceiver 120. Transceiver120 includes a transmitter 122, a receiver 124, a controller 126, and anoptical interface 128. Transmitter 122 includes a laser 130, a memory134, an interface 136, a modulator and bias digital-to-analog converter(DAC) 138, and a flag 146. Receiver 124 includes an analog-to-digitalconverter (ADC) 140. Controller 126 includes firmware 142 and a memory144.

[0015] Host 110 may be any type of wired or wireless device configuredto operate in conjunction with transceiver 120. Host 110 is external totransceiver 120. Examples of such devices include a test system, aserver computer system, a personal computer system, a laptop computersystem, a handheld computer system, a personal digital assistant, and amobile telephone.

[0016] Transceiver 120 comprises an optical transceiver configured tocommunicate with host 110 by sending and receiving electrical signals asdescribed in additional detail herein below. Transceiver 120 alsocommunicates with another device (not shown) by sending and receivingoptical signals using optical interface 128. Optical interface 128 maybe a Fibre Channel interface or another type of optical interface.

[0017] In one embodiment, transceiver 120 conforms to the SFF-8472Specification for Digital Diagnostic Monitoring Interface for OpticalTransceivers as set forth by the SFF (Small Form Factor) Committee. Inother embodiments, transceiver 120 may conform to other specifications.

[0018] In operation, transmitter 122 comprises an optical transmitterconfigured to receive digital output signals from host 110 using aconnection 152. Modulator and bias DAC 138 converts the digital outputsignals to analog output signals and provides the analog output signalsto laser 130. The digital output signals and the analog output signalscomprise electrical signals. Laser 130 generates optical output signalsin response to the analog output signals and provides the optical outputsignals to optical interface 128 using a connection 154.

[0019] Receiver 124 comprises an optical receiver configured to receiveoptical input signals from optical interface 128 using a connection 156.Analog-to-digital converter 140 converts the optical input signals fromanalog input signals to digital input signals and provides the digitalinput signals to host 110 using a connection 158. The digital outputsignals and the analog output signals comprise electrical signals.

[0020] Transceiver 120 also communicates with host 110 using anelectrical connection 160. In particular, transceiver 120 receivescontrol signals from host 110 using connection 160. Transceiver 120 alsoprovides information to host 110 using connection 160. In the embodimentof FIG. 1, electrical connection 160 couples host 110 to transmitter 122and is an I2C connection, as provided by the I2C-Bus Specificationavailable from Philips Semiconductors athttp://www.semiconductors.philips.com/acrobat/various/I2C_BUS_SPECIFICATION_(—)3.pdf, and interface 136 comprises an I2C bus interface. Inaddition, connection 160 and interface 136 conform to the 2-wire serialCMOS EEPROM protocol defined for the ATMEL AT24C01A/02/04 family ofcomponents, as provided by the ATMEL AT24C01A/02/04 Data Sheet availablefrom Atmel at http://www.atmel.com/atmel/acrobat/doc( )180.pdf Interface136 may comprise hardware or a combination of hardware and softwarecomponents. Memory 134 may be any type of volatile or non-volatilememory configured to store information. In one embodiment of FIG. 1,memory 134 comprises SRAM.

[0021] Controller 126 provides control signals to and receives feedbacksignals from transmitter 122 and receiver 124 using a connection 164. Inthe embodiment of FIG. 1, connection 164 is an internal 12C connection,as provided by the I2C-Bus Specification available from PhilipsSemiconductors athttp://www.semiconductors.philips.com/acrobat/various/I2C_BUS_SPECIFICATION_(—)3.pdf, where controller 126 acts as a master and transmitter 122and receiver 124 act as slaves. In other embodiments, connection 164 maybe any other type of serial or parallel connection.

[0022] Controller 126 includes firmware 142 that is executable bycontroller 126 to cause the control signals to be generated and thefeedback signals to be received and processed. In other embodiments,controller 126 may include other combinations of hardware and/orfirmware or software to perform the functions described herein. Memory144 may be any type or combination of volatile and non-volatile storageincluding registers, flash memory, RAM, or EEPROM.

[0023] Transceiver 120 includes at least two modes of operation: testmode and customer mode. In both modes, transceiver 120 operates inconjunction with host 110. In the test mode of operation, host 110causes calibration steps to be performed on transceiver 120. Thecalibration steps include storing information in transceiver 120 andcalibrating and/or tuning transmitter 122, receiver 124, and othercomponents of transceiver 120. The information stored may includemanufacturing information, production information, device information,revision information, transmitter 122 settings and parameters includingcalibration constants of laser 130, receiver 124 settings and parametersincluding optical modulation amplitude (OMA) tables, clock information,temperature coefficient information, temperature/Vcc calibrationconstants, and EEPROM information.

[0024] In the test mode of operation, transceiver 120 may perform a selftest on components of transceiver 120 to verify the functionality andrevision information of each component in the test mode of operation. Inaddition, transceiver 120 provides state information such as registercontents from components of transceiver 120 to host 110. Transceiver 120may further perform internal monitoring tasks in the test mode ofoperation.

[0025] In the test mode of operation, transceiver 120 performscalibration steps in response to requests from host 110. Host 110provides a request associated with a calibration step to transceiver 120using interface 136. The request may include a command, an address, andinformation associated with the command and may include a device addressassociated with controller 126. Interface 136 causes the request to bestored in memory 134 using a connection 161. In response to the request,interface 136 causes flag 146 to be set using a connection 162 to signalcontroller 126 that a request has been received. Controller 126periodically polls flag 146 using a connection 163 and, in response todetermining that flag 146 has been set by interface 136, controller 126accesses the request in memory 134 using the connection 164.

[0026] Controller 126 processes the request by performing thecalibration step associated with the request. In response to completingthe step, controller 126 stores an indicator in memory 144 thatindicates that the step has been performed. Controller 126 also providesan indicator to host 110 by storing the indicator in memory 134 usingconnection 164 and clearing flag 146 using connection 163. Interface 136detects the indicator in memory 134 either by detecting that flag 146has been cleared or by monitoring stores to memory 134. In response todetecting the indicator, interface 136 provides the indicator to host110. Host 110 stores the indicator in a memory (not shown). Host 110 maythen cause additional calibration steps to be performed in the mannerjust described.

[0027] After controller 126 completes a calibration step, controller 126accesses information in memory 144 to determine whether all calibrationsteps have been completed. The information includes indicatorsassociated with each calibration step that indicate whether each stephas been performed successfully. If a step has either not been performedor not been performed successfully, controller 126 causes transceiver120 to remain in the test mode of operation. If all steps have beenperformed successfully, then controller 126 causes transceiver 120 toenter the customer mode of operation.

[0028] Host 110 may also determine whether all calibration steps havebeen completed successfully using the indicator received fromtransceiver 120 for each calibration step. The indicators indicatewhether each calibration step has been completed successfully andwhether any errors were encountered. Host 110 may also provide a requestto transceiver 120 to cause transceiver 120 to exit the test mode ofoperation. In response to the exit test mode request transceiver 120provides a indicator that indicates which, if any, of the calibrationsteps performed on transceiver 120 did not complete successfully. Inresponse to determining that one or more calibration steps did notcomplete successfully, host 110 may perform failure analysis functionson transceiver 120. In response to determining that all calibrationsteps completed successfully, host 110 may determine that transceiver120 is ready to provide to a customer or end user.

[0029] In the customer mode of operation, transceiver 120 operatesnormally in conjunction with host 110. In particular, transceiver 120receives electrical signals from host 110, converts the electricalsignals to optical signals, and provides the optical signals to anotherdevice (not shown) using optical interface 128. In addition, transceiver120 receives optical signals from the other device across opticalinterface 128, converts the optical signals to electrical signals, andprovides the electrical signals to host 110. At any time during thecustomer mode of operation, host 110 can cause transceiver 120 tore-enter the test mode of operation by providing a request to enter testmode to transceiver 120.

[0030]FIG. 2 is a flow chart illustrating an embodiment of a method forchanging modes of operation in a transceiver. The embodiment of themethod of FIG. 2 will be described with reference to FIG. 1. In FIG. 2,a determination is made by controller 126 as to whether all calibrationsteps of transceiver 120 have been completed as indicated in a block202. This determination may be made in response to transceiver 120 beingpowered up (i.e. turned on) or reset.

[0031] If all calibration steps of transceiver 120 have been completed,then transceiver 120 enters a customer mode of operation as indicated ina block 204. A determination is made as to whether controller 126detects a request to enter test mode from host 110 as indicated in ablock 206. If controller 126 detects a request to enter test mode, thentransceiver enters a test mode of operation as indicated in a block 208.

[0032] If all calibration steps of transceiver 120 have not beencompleted, then transceiver 120 enters the test mode of operationindicated in block 208. A determination is made as to whether controller126 has detected a request from host 110 as indicated in a block 210.Controller 126 may detect the request by polling flag 146. If controller126 has not detected a request from host 110, then the method repeatsthe function of block 210 at a later time. If controller 126 hasdetected a request from host 110, then controller 126 accesses therequest as indicated in a block 212. Controller 126 accesses the requestfrom memory 134. Controller 126 processes the request as indicated in ablock 214.

[0033] A determination is made as to whether the request was completedsuccessfully as indicated in a block 216. If the request was notcompleted successfully, then controller 126 causes an error indicator tobe stored in memory 144 as indicated in a block 218. Controller 126 alsocauses an error indicator to be provided to host 110 as indicated in ablock 220. The error indicator is provided to host 110 using memory 134and interface 136.

[0034] If the request was completed successfully, then controller 126causes a success indicator to be stored in memory 144 as indicated in ablock 222. Controller 126 also causes a success indicator to be providedto host 110 as indicated in a block 224. The success indicator isprovided to host 110 using memory 134 and interface 136.

[0035]FIG. 3 is a flow chart illustrating an embodiment of a method forinteracting with a transceiver in a test mode of operation. Theembodiment of the method of FIG. 3 will be described with reference toFIG. 1. In FIG. 3, host 110 provides a request to transceiver 120 asindicated in a block 302. The request may be a request to perform acalibration step or a request to enter test mode. A request to entertest mode causes transceiver 120 to enter the test mode of operation anda request to perform a calibration step causes the calibration step tobe performed on transceiver 120. A determination is made by host 110 asto whether host 110 has received an indicator associated with therequest as indicated in a block 304. If host 110 has not received anindicator associated with the request, then host 110 detects an errorcondition associated with transceiver 120 as indicated by a block 306and the method ends. If host 110 does not receive the indicator, then anerror condition may be assumed because transceiver 120 is configured toprovide the indicator in response to performing the calibration stepwhether or not the calibration step is successful.

[0036] If host 110 has received an indicator associated with therequest, then host 110 stores the indicator as indicated in a block 308.A determination is made by host 110 as to whether there are additionalcalibration steps to be performed as indicated in a block 310. If thereare additional calibration steps to be performed, then the methodrepeats the function of block 302. If there are no additionalcalibration steps to be performed, then the method ends.

[0037]FIG. 4 is a flow chart illustrating an embodiment of a method fordetecting errors from a test mode of operation of a transceiver. Theembodiment of the method of FIG. 4 will be described with reference toFIG. 1. In FIG. 4, host 110 examines the stored indicators from thecalibration steps as indicated in a block 402. A determination is madeby host 110 as to whether any errors were detected using the indicatorsas indicated in a block 404. If any errors were detected, then host 110analyzes the failing transceiver 120 as indicated by a block 406 and themethod ends. If no errors were detected, then host 110 indicates thattransceiver 120 is ready to ship as indicated in a block 308.

[0038] In an alternative embodiment of FIG. 4, host 110 may detect anerror immediately in response to storing an indicator associated with acalibration step. In response to the error, host 110 may attempt torepair the failure or may perform one or more failure analysis functionson failing transceiver 120.

[0039]FIG. 5 is a block diagram illustrating an alternative embodimentof a system that includes a transceiver with a test mode of operation.The embodiment of FIG. 5 operates in substantially the same way as theembodiment of FIG. 1 as described with reference to FIGS. 2-4. In FIG.5, however, cache 134 and interface 136 are not included in transmitter122. This embodiment illustrates that cache 134 and interface 136 may beincluded in any other portion or component transceiver 120.

[0040] Although specific embodiments have been illustrated and describedherein for purposes of description of the preferred embodiment, it willbe appreciated by those of ordinary skill in the art that a wide varietyof alternate and/or equivalent implementations calculated to achieve thesame purposes may be substituted for the specific embodiments shown anddescribed without departing from the scope of the present invention.Those with skill in the chemical, mechanical, electromechanical,electrical, and computer arts will readily appreciate that the presentinvention may be implemented in a very wide variety of embodiments. Thisapplication is intended to cover any adaptations or variations of thepreferred embodiments discussed herein. Therefore, it is manifestlyintended that this invention be limited only by the claims and theequivalents thereof.

What is claimed is:
 1. A system comprising: a host; and a transceivercoupled to the host; wherein the transceiver is configured to receive afirst request from a host, and wherein the transceiver is configured tocause a test mode of operation to be entered in response to receivingthe first request.
 2. The system of claim 1 wherein the first request isconfigured to cause the transceiver to enter the test mode of operation.3. The system of claim 1 wherein the transceiver operates in a customermode of operation prior to entering the test mode of operation.
 4. Thesystem of claim 1 wherein the transceiver is configured to receive asecond request from a host, and wherein the transceiver is configured toperform a calibration step in response to receiving the second request.5. The system of claim 4 wherein the calibration step includes storinginformation received from the host in the transceiver.
 6. The system ofclaim 4 wherein the calibration step includes calibrating a component ofthe transceiver.
 7. The system of claim 4 wherein the transceiver isconfigured to store an indicator associated with the second request inresponse to performing the calibration step, and wherein the indicatorindicates whether the calibration step was performed successfully by thetransceiver.
 8. The system of claim 4 wherein the transceiver isconfigured to provide an indicator associated with the second request tothe host in response to performing the calibration step, and wherein thehost is configured to determine whether the calibration step wasperformed successfully by the transceiver using the indicator.
 9. Thesystem of claim 1 wherein the transceiver includes a controller, aninterface, and a memory coupled to the interface and the controller,wherein the interface is configured to store the first request in thememory, and wherein the controller is configured to access the firstrequest from the memory.
 10. The system of claim 1 wherein thetransceiver comprises an optical transceiver.
 11. A transceivercomprising: a controller; and a first memory coupled to the controllerand including first information; wherein the controller is configured toaccess the first information, and wherein the controller is configuredto enter a test mode of operation in response to the first informationindicating that a calibration step has not been completed.
 12. Thetransceiver of claim 111 wherein the controller is configured to accessthe first information in response to being powered up.
 13. Thetransceiver of claim 11 wherein the controller is configured to enter acustomer mode of operation in response to the first informationindicating that the calibration step has been completed.
 14. Thetransceiver of claim 11 wherein the controller is configured to receivea request associated with the calibration step from a host, and whereinthe controller is configured to perform the first calibration step inresponse to receiving the request.
 15. The transceiver of claim 14wherein the controller is configured to enter a customer mode ofoperation in response to performing the first calibration step.
 16. Thetransceiver of claim 14 wherein the controller is configured to providean indicator to the host in response to detecting an error associatedwith the calibration step.
 17. The transceiver of claim 14 wherein thecontroller is configured to provide an indicator to the host in responseto detecting that the calibration step has completed successfully. 18.The transceiver of claim 11 further comprising: a laser configured toreceive electrical signals from the host and configured to generateoptical signal signals in response to the electrical signals.
 19. Amethod comprising: determining whether all calibration steps have beenperformed on a transceiver; entering a test mode of operation of thetransceiver in response to determining that all calibration steps havenot been performed; and entering a customer mode of operation of thetransceiver in response to determining that all calibration steps havebeen performed.
 20. The method of claim 19 further comprising: inresponse to entering the test mode of operation: receiving a requestfrom a host by the transceiver; and performing a calibration stepassociated with the request on the transceiver;
 21. The method of claim19 further comprising: subsequent to performing the calibration stepassociated with the request: determining whether all calibration stepshave been performed on the transceiver; and entering the customer modeof operation of the transceiver in response to determining that allcalibration steps have been performed.
 22. The method of claim 21further comprising: providing an indicator associated with thecalibration step from the transceiver to the host in response toperforming the calibration step.
 23. The method of claim 21 furthercomprising: storing an indicator associated with the calibration step inthe transceiver in response to performing the calibration step.
 24. Themethod of claim 23 further comprising: determining whether allcalibration steps have been performed on the transceiver using theindicator.
 25. A system comprising: a host; and a transceiver coupled tothe host; wherein the host include a first means for providing a requestto the transceiver during a test mode of operation of the transceiver,wherein the transceiver includes a second means for processing therequest, and wherein the transceiver includes a third means forproviding an indicator associated with the request to the host.
 26. Thesystem of claim 25 wherein the transceiver includes a fourth means forreceiving the request from the host and for providing a signal to thesecond means indicating that the request has been received.
 27. Thesystem of claim 26 wherein the second means is for accessing therequest.
 28. The system of claim 25 wherein the transceiver includes afourth means for causing the transceiver to enter a customer mode ofoperation in response to determining that all calibration steps havebeen performed.
 29. The system of claim 25 wherein the transceiverincludes a transmitter configured to receive electrical signals from thehost and configured to generate optical signals in response to theelectrical signals.